1. Field of the Invention
The present disclosure relates to a pyroelectric temperature sensor and a method for measuring the temperature with a pyroelectric temperature sensor.
2. Description of the Related Art
An amount of charge on the surface of a pyroelectric body increases or decreases depending on temperature change. This is referred to as pyroelectric effect. A pyroelectric temperature sensor detects temperature by utilizing the pyroelectric effect. Japanese Laid-open patent publication No. Hei 2-137268 (Hereinafter, Patent document 1) discloses a conventional pyroelectric temperature sensor comprising a structure of a pyroelectric body and a semiconductor.
FIG. 14 shows a cross-sectional view of the conventional pyroelectric temperature sensor disclosed in the patent document 1. The conventional pyroelectric temperature sensor comprises a pyroelectric film 101, a sensor electrode 102, a semiconductor film 103, a source electrode 104, a drain electrode 105, an interlayer insulation film 106, and an extraction electrode 107.
By the pyroelectric effect due to temperature change, a potential at the position near the interface between the pyroelectric film 101 and the semiconductor layer 103 is modulated. The modulation forms a channel layer or a depletion layer in the semiconductor layer 103. The formation of the channel layer or the depletion layer changes electroconductivity of the semiconductor layer 103 greatly. Thus, the temperature change in the pyroelectric film is converted into change of the amount of a drain current of a thin film transistor formed in the semiconductor layer 103.
However, according to the patent document 1, it is impossible to obtain an amplification characteristic greater than that of the thin film transistor. Furthermore, detection of the amount of the drain current requires a complicated external circuit.